Parameters of the BMS

This page shows the parameters of the BMS.

This page will describe the variables of the BMS. There are 6 kind of parameters

1. The common battery variables

2. The calculated battery variables

3. The additional battery variables

4. The configuration variables

5. The CAN variables

6. The hardware parameters

In the console (CLI) type "bms get all" to get all the parameters and its current value.

In the console (CLI) type: "bms help parameters" to get more info on the parameters.

The BMS parameter lists

The common battery variables list

Table 1. Common battery variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
v-out	V	float	The voltage of the BMS output	0	RO	0
v-batt	V	float	The voltage of the battery pack	0	RO	1
n-cells	-	uint8_t	Number of cells used in the BMS board	3	RW	2
v-cell1	V	float	The voltage of cell 1	0	RO	3
v-cell2	V	float	The voltage of cell 2	0	RO	4
v-cell3	V	float	The voltage of cell 3	0	RO	5
v-cell4	V	float	The voltage of cell 4	0	RO	6
v-cell5	V	float	The voltage of cell 5	0	RO	7
v-cell6	V	float	The voltage of cell 6	0	RO	8
i-batt	A	float	The last recorded current of the battery	0	RO	9
i-batt-avg	A	float	The average current since the last measurement (period t-meas (default 1s))	0	RO	10
i-batt-10s-avg	A	float	The 10s rolling average current, updated each t-meas, default 1000 (ms)	0	RO	11
sensor-enable	-	bool	This variable is used to enable or disable the battery temperature sensor, 0 is disabled, 1 is enabled	0	RW	12
c-batt	C	float	The temperature of the external battery temperature sensor	0	RO	13
c-afe	C	float	The temperature of the analog front end	0	RO	14
c-t	C	float	The temperature of the transistor (switch)	0	RO	15
c-r	C	float	The temperature of the sense resistor	0	RO	16

The calculated battery variables list

Table 2. Calculated battery variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
p-avg	W	float	Average power consumption over the last 10 seconds.	0	RO	17
e-used	Wh	float	Power consumption since device boot	0	RO	18
t-full	h	float	Charging is expected to complete in this time; zero if not charging.	0	RO	19
a-rem	Ah	float	Remaining capacity in the battery	0	RW	20
a-full	Ah	float	Full charge capacity, predicted battery capacity when it is fully charged. Decreases with aging.	4.6	RW	21
a-factory	Ah	float	Battery capacity stated by the factory	4.6	RW	22
s-charge	%	uint8_t	Percentage of the full charge 0 - 100%.	0	RO	23
s-health	%	uint8_t	Health of the battery in percentage, use STATE_OF_HEALTH_UNKNOWN = 127 if cannot be estimated.	127	RO	24
s-out	-	bool	This is true if the output power is enabled.	0	RO	25
s-in-flight	-	bool	This is true if the system is in flight (with flight-mode-enable and i-flight-mode)	0	RO	26
batt-id	-	uint8_t	Identifies the battery within this vehicle, 0 - primary battery.	0	RW	27

The additional battery variables list

Table 3. Additional battery variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
v-cell-ov	V	float	Battery maximum allowed voltage for one cell. exceeding this voltage, the BMS will go to fault mode	4.2	RW	28
v-cell-uv	V	float	Battery minimum allowed voltage for one cell. Going below this voltage, the BMS will go to fault mode followed by deepsleep after t-fault-timeout	3	RW	29
v-cell-nominal	V	float	Battery nominal voltage for one cell. will be used for energy calculation.	3.7	RW	30
v-storage	V	float	The voltage what is specified as storage voltage for a cell	3.8	RW	31
v-cell-margin	mV	uint8_t	Cell voltage charge margin to decide or not to go through another topping charge cycle	50	RW	32
v-recharge-margin	mV	Uint16_t	Cell voltage charge complete margin to decide or not to do a battery re-charge, to keep the cell voltages at max this much difference with the cell-ov	200	RW	33
i-peak-max	A	float	Maximum peak current threshold to open the switch during normal operation, can't be overruled	200	RW	34
i-out-max	A	float	Maximum current threshold to open the switch during normal operation, if not overruled	60	RW	35
i-out-nominal	A	float	Nominal discharge current (informative only)	60	RW	36
i-flight-mode	A	uint8_t	Current threshold to not disable the power in flight mode	5	RW	37
i-sleep-oc	mA	uint8_t	Overcurrent threshold detection in sleep mode that will wake up the BMS and also the threshold to detect the battery is not in use	30	RW	38
i-system	mA	uint8_t	Current of the BMS board itself, this is measured (as well) during charging, so this needs to be subtracted	40	RW	39
i-charge-max	A	float	Maximum current threshold to open the switch during charging	4.6	RW	40
i-charge-nominal	A	float	Nominal charge current (informative only)	4.6	RW	41
i-charge-full	mA	uint16_t	Current threshold to detect end of charge sequence	50	RW	42
c-cell-ot	C	float	Over temperature threshold for the cells. Going over this threshold and the BMS will go to FAULT mode	45	RW	43
c-cell-ut	C	float	Under temperature threshold for the cells. Going under this threshold and the BMS will go to FAULT mode	-20	RW	44
c-pcb-ot	C	float	PCB Ambient temperature over temperature threshold	45	RW	45
c-pcb-ut	C	float	PCB Ambient temperature under Temperature threshold	-20	RW	46
c-cell-ot-charge	C	float	Over temperature threshold for the cells During charging. Going over this threshold and the BMS will go to FAULT mode.	40	RW	47
c-cell-ut-charge	C	float	Under temperature threshold for the cells during charging. Going under this threshold during charging and the BMS will go to FAULT mode	0	RW	48
n-charges	-	uint16_t	The number of charges done	0	RW	49
n-charges-full	-	uint16_t	The number of complete charges	0	RW	50
ocv-slope	mV/A.min	float	The slope of the OCV curve. This will be used to calculate the balance time.	5.3	RW	51
battery-type	-	uint8_t	The type of battery attached to it. 0 = LiPo, 1 = LiFePO4, 2 = LiFeYPO4, 3 = NMC (LiPo type, LiNiMnCoO2), 4 = Na-ion (Sodium-ion, SIB). Could be extended. Will change OV, UV, v-storage, OCV/SoC table if changed runtime.	3	RW	52

The configuration variables list

Table 4. Configuration variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
t-meas	ms	uint16_t	Cycle of the battery to perform a complete battery measurement and SOC estimation can only be 10000 or a whole division of 10000 (For example: 5000, 1000, 500)	1000	RW	53
t-ftti	ms	uint16_t	Cycle of the battery to perform diagnostics (Fault Tolerant Time Interval)	1000	RW	54
t-bms-timeout	s	uint16_t	Timeout for the BMS to go to SLEEP mode when the battery is not used.	600	RW	55
t-fault-timeout	s	uint16_t	After this timeout, with an undervoltage fault the battery will go to DEEPSLEEP mode to preserve power. 0 sec is disabled.	60	RW	56
t-bcc-sleep-cyclic	s	uint8_t	Wake up cyclic timing of the AFE (after front end) during sleep mode	1	RW	57
t-sleep-timeout	h	uint8_t	When the BMS is in sleep mode for this period it will go to the self-discharge mode, 0 if disabled.	24	RW	58
t-ocv-cyclic0	s	int32_t	OCV measurement cyclic timer start (timer is increase by 50% at each cycle)	300	RW	59
t-ocv-cyclic1	s	int32_t	OCV measurement cyclic timer final value (limit)	86400	RW	60
t-charge-detect	s	uint8_t	During NORMAL mode, if the battery current is positive for more than this time, then the BMS will go to CHARGE mode	1	RW	61
t-cb-delay	s	uint8_t	Time for the cell balancing function to start after entering the CHARGE mode	120	RW	62
t-charge-relax	s	uint16_t	Relaxation time after the charge is complete before going to another charge round.	300	RW	63
batt-eol	%	uint8_t	Percentage at which the battery is end-of-life and shouldn’t be used anymore Typically between 90%-50%	80	RW	64
s-flags	-	uint8_t	This contains the status flags as described in BMS_status_flags_t	255	RO	65
self-discharge-enable	-	bool	This variable is used to enable or disable the SELF_DISCHARGE state, 0 is disabled, 1 is enabled	1	RW	66
flight-mode-enable	-	bool	This variable is used to enable or disable flight mode, is used together with i-flight-mode. 0 is disabled	0	RW	67
emergency-button-enable	-	bool	This variable is used to enable or disable the emergency button on PTE8.	0	RW	68
smbus-enable	-	bool	This variable is used to enable or disable the SMBus update.	0	RW	69
gate-check-enable	-	bool	This variable is used to enable or disable the gate safety check. If true, it will check if it can be turned off, based on output voltage.	1	RW	70
model-id	-	uint64_t	Model id, set to 0 if not applicable	0	RW	71
model-name	-	char[32]	Battery model name, model name is a human-readable string that could include the vendor, model, chemistry.	"BMS772"	RW	72

The can variables list

Table 5. Can variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
cyphal-node-static-id*	-	uint8_t	This is the node ID of the CYPHAL node. Should be between 1 - 127 or 255 for PNP.	255	RW	73
cyphal-es-sub-id*	-	uint16_t	This is the subject ID of the energy source CYPHAL message (1...100Hz)	4096	RW	74
cyphal-bs-sub-id*	-	uint16_t	This is the subject ID of the battery status CYPHAL message (1Hz)	4097	RW	75
cyphal-bp-sub-id*	-	uint16_t	This is the subject ID of the battery parameters CYPHAL message (0.2Hz)	4098	RW	76
cyphal-legacy-bi-sub-id*	-	uint16_t	This is the subject ID of the battery info legacy CYPHAL message (0.2 ~ 1Hz)	65535	RW	77
dronecan-node-static-id	-	uint8_t	This is the node ID of the DRONECAN node. Should be between 1 - 127 or 255 for dynamic node id.	0	RW	78
dronecan-bat-continuous	-	uint8_t	This indicates if the particular DroneCAN topic has to be published	0	RW	79
dronecan-bat-periodic	-	uint8_t	This indicates if the particular DroneCAN topic has to be published	0	RW	80
dronecan-bat-cells	-	uint8_t	This indicates if the particular DroneCAN topic has to be published	0	RW	81
dronecan-bat-info	-	uint8_t	This indicates if the particular DroneCAN topic has to be published	1	RW	82
dronecan-bat-info-aux	-	uint8_t	This indicates if the particular DroneCAN topic has to be published	1	RW	83
can-mode	-	char[32]	Options “OFF”, "DRONECAN" and "CYPHAL". To indicate which is used.	“OFF”	RW	84
can-fd-mode*	-	uint8_t	If true CANFD is used, otherwise classic CAN is used	0	RW	85
can-bitrate*	bit/s	int32_t	The bitrate of classical can or CAN FD arbitration bitrate	1000000	RW	86
can-fd-bitrate*	bit/s	int32_t	The bitrate of CAN FD data bitrate	4000000	RW	87

A line means this is not implemented yet.

* These parameters will only be implemented during startup of the BMS

The hardware parameters

Table 6. BMS hardware parameters list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
v-min	V	uint8_t	Minimum stack voltage for the BMS board to be fully functional	6	RW	88
v-max	V	uint8_t	Maximum stack voltage allowed by the BMS board	26	RW	89
i-range-max	A	uint16_t	Maximum current that can be measured by the BMS board	300	RW	90
i-max	A	uint8_t	Maximum DC current allowed in the BMS board (limited by power dissipation in the MOSFETs). For info only. Use i-out-max for a limit.	60	RW	91
i-short	A	uint16_t	Short circuit current threshold (typical: 550A, min: 500A, max: 600A)	500	RW	92
t-short	us	uint8_t	Blanking time for the short circuit detection	20	RW	93
i-bal	mA	uint8_t	Cell balancing current under 4.2V with cell balancing resistors of 82 ohms	50	RW	94
m-mass	kg	float	The total mass of the (smart) battery	0	RW	95
f-v-out-divider-factor	-	float	The factor of the output voltage divider as component tolerances could be different to not result in 11.0.	11.0	RW	96

A line means this is not implemented yet.